In a medium bowl, whisk together brown rice flour, white rice flour, potato starch, tapioca flour, cornstarch and xanthan gum. Set aside. Cream butter and powdered sugar in a large bowl with an electric mixer. Mix in egg, vanilla, almond extract and salt and beat until mixed well. Gradually add in flour (1/2 cup at a time) and mix after each addition. Be sure not to over mix. I use the electric mixer for the first 2 cups of flour and then hand mix the last 1/2 cup. Put dough in the refrigerator for an hour or so, or until the dough firms up. You can also put it in the freezer but I would only do that for 20-30 minutes otherwise it’s very difficult to roll out. Sprinkle your work surface and rolling pin with powdered sugar. Roll the dough out to a 1/4 inch thickness. Cut with cookie cutters. Place on a greased cookie sheet and put back in the freezer for 10-15 minutes. Then, bake in the oven at 375 degrees Fahrenheit for 8-10 minutes or until cookie all the way through. The cookie should not brown, but the edges can be slightly browned (that’s a good indication it’s done). Cool on a wire rack.
In a bowl of an electric mixer fitted with the whisk attachment, combine the powdered sugar, meringue powder and water. Mix for 7-10 minutes, until the ingredients are well blended and the icing has a matte finish. This is the base consistency. I usually add about 1 tsp more of water for a good outline icing (I use a 10 second rule) and add more water until I reach a 4-second icing for flood icing. This means that when you drizzle icing over the bowl of royal icing then the icing will flow back in with the rest of the icing in 4 seconds (10 second icing is the same but it will sink back in with the rest of the icing in 10 seconds). If you need to thin it out more then add more water. If you need to thicken it add more powdered sugar.
To decorate the cookie, I used an egg shaped cookie cutter. Outline the cookie using purple icing (10 second icing). Flood with thinned out icing (4 second icing). Allow to dry completely. Using 10 second icing in pastry bags fitted with a number 1 tip, decorate the cookie. You can follow my design in the pictogram below. Allow to dry completely.
Follow my pictogram below to use the same design I did!